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<div  id='write'  class = 'is-node'><div class='md-toc' mdtype='toc'><p class="md-toc-content"><span class="md-toc-item md-toc-h2" data-ref="n2"><a class="md-toc-inner" href="#header-n2">1:final关键字(掌握)</a></span><span class="md-toc-item md-toc-h4" data-ref="n3"><a class="md-toc-inner" href="#header-n3">(1)是最终的意思，可以修饰类，方法，变量。</a></span><span class="md-toc-item md-toc-h4" data-ref="n4"><a class="md-toc-inner" href="#header-n4">(2)特点：</a></span><span class="md-toc-item md-toc-h6" data-ref="n5"><a class="md-toc-inner" href="#header-n5">A:它修饰的类，不能被继承。</a></span><span class="md-toc-item md-toc-h6" data-ref="n6"><a class="md-toc-inner" href="#header-n6">B:它修饰的方法，不能被重写。</a></span><span class="md-toc-item md-toc-h6" data-ref="n7"><a class="md-toc-inner" href="#header-n7">C:它修饰的变量，是一个常量。</a></span><span class="md-toc-item md-toc-h4" data-ref="n8"><a class="md-toc-inner" href="#header-n8">(3)面试相关：</a></span><span class="md-toc-item md-toc-h6" data-ref="n9"><a class="md-toc-inner" href="#header-n9">A:局部变量</a></span><span class="md-toc-item md-toc-h6" data-ref="n14"><a class="md-toc-inner" href="#header-n14">B:初始化时机</a></span><span class="md-toc-item md-toc-h2" data-ref="n21"><a class="md-toc-inner" href="#header-n21">2:多态(掌握)</a></span><span class="md-toc-item md-toc-h4" data-ref="n22"><a class="md-toc-inner" href="#header-n22">(1)同一个对象在不同时刻体现出来的不同状态。</a></span><span class="md-toc-item md-toc-h4" data-ref="n23"><a class="md-toc-inner" href="#header-n23">(2)多态的前提：</a></span><span class="md-toc-item md-toc-h4" data-ref="n44"><a class="md-toc-inner" href="#header-n44">(3)多态中的成员访问特点</a></span><span class="md-toc-item md-toc-h6" data-ref="n45"><a class="md-toc-inner" href="#header-n45">A:成员变量</a></span><span class="md-toc-item md-toc-h6" data-ref="n47"><a class="md-toc-inner" href="#header-n47">B:构造方法</a></span><span class="md-toc-item md-toc-h6" data-ref="n49"><a class="md-toc-inner" href="#header-n49">C:成员方法</a></span><span class="md-toc-item md-toc-h6" data-ref="n51"><a class="md-toc-inner" href="#header-n51">D:静态方法</a></span><span class="md-toc-item md-toc-h4" data-ref="n53"><a class="md-toc-inner" href="#header-n53">(4)多态的好处：</a></span><span class="md-toc-item md-toc-h6" data-ref="n54"><a class="md-toc-inner" href="#header-n54">A:提高代码的维护性(继承体现)</a></span><span class="md-toc-item md-toc-h6" data-ref="n55"><a class="md-toc-inner" href="#header-n55">B:提高代码的扩展性(多态体现)</a></span><span class="md-toc-item md-toc-h4" data-ref="n56"><a class="md-toc-inner" href="#header-n56">(5)多态的弊端：</a></span><span class="md-toc-item md-toc-h4" data-ref="n59"><a class="md-toc-inner" href="#header-n59">(6)多态中的转型</a></span><span class="md-toc-item md-toc-h4" data-ref="n61"><a class="md-toc-inner" href="#header-n61">(7)孔子装爹的案例帮助大家理解多态</a></span><span class="md-toc-item md-toc-h4" data-ref="n62"><a class="md-toc-inner" href="#header-n62">(8)多态的练习</a></span><span class="md-toc-item md-toc-h2" data-ref="n64"><a class="md-toc-inner" href="#header-n64">3:抽象类(掌握)</a></span><span class="md-toc-item md-toc-h4" data-ref="n65"><a class="md-toc-inner" href="#header-n65">(1)把多个共性的东西提取到一个类中，这是继承的做法。</a></span><span class="md-toc-item md-toc-h4" data-ref="n67"><a class="md-toc-inner" href="#header-n67">(2)抽象类的特点</a></span><span class="md-toc-item md-toc-h6" data-ref="n68"><a class="md-toc-inner" href="#header-n68">A:抽象类和抽象方法必须用关键字abstract修饰</a></span><span class="md-toc-item md-toc-h6" data-ref="n69"><a class="md-toc-inner" href="#header-n69">B:抽象类中不一定有抽象方法,但是有抽象方法的类一定是抽象类</a></span><span class="md-toc-item md-toc-h6" data-ref="n70"><a class="md-toc-inner" href="#header-n70">C:抽象类不能实例化</a></span><span class="md-toc-item md-toc-h6" data-ref="n71"><a class="md-toc-inner" href="#header-n71">D:抽象类的子类</a></span><span class="md-toc-item md-toc-h4" data-ref="n76"><a class="md-toc-inner" href="#header-n76">(3)抽象类的成员特点：</a></span><span class="md-toc-item md-toc-h6" data-ref="n78"><a class="md-toc-inner" href="#header-n78">A:成员变量</a></span><span class="md-toc-item md-toc-h6" data-ref="n80"><a class="md-toc-inner" href="#header-n80">B:构造方法</a></span><span class="md-toc-item md-toc-h6" data-ref="n82"><a class="md-toc-inner" href="#header-n82">C:成员方法</a></span><span class="md-toc-item md-toc-h4" data-ref="n84"><a class="md-toc-inner" href="#header-n84">(4)抽象类的练习</a></span><span class="md-toc-item md-toc-h4" data-ref="n86"><a class="md-toc-inner" href="#header-n86">(5)抽象类的几个小问题</a></span><span class="md-toc-item md-toc-h6" data-ref="n87"><a class="md-toc-inner" href="#header-n87">A:抽象类有构造方法，不能实例化，那么构造方法有什么用?</a></span><span class="md-toc-item md-toc-h6" data-ref="n89"><a class="md-toc-inner" href="#header-n89">B:一个类如果没有抽象方法,却定义为了抽象类，有什么用?</a></span><span class="md-toc-item md-toc-h6" data-ref="n91"><a class="md-toc-inner" href="#header-n91">C:abstract不能和哪些关键字共存</a></span><span class="md-toc-item md-toc-h2" data-ref="n93"><a class="md-toc-inner" href="#header-n93">4:接口(掌握)</a></span><span class="md-toc-item md-toc-h4" data-ref="n94"><a class="md-toc-inner" href="#header-n94">(1)回顾猫狗案例，它们仅仅提供一些基本功能。</a></span><span class="md-toc-item md-toc-h4" data-ref="n96"><a class="md-toc-inner" href="#header-n96">(2)接口的特点：</a></span><span class="md-toc-item md-toc-h6" data-ref="n97"><a class="md-toc-inner" href="#header-n97">A:接口用关键字interface修饰</a></span><span class="md-toc-item md-toc-h6" data-ref="n99"><a class="md-toc-inner" href="#header-n99">B:类实现接口用implements修饰</a></span><span class="md-toc-item md-toc-h6" data-ref="n101"><a class="md-toc-inner" href="#header-n101">C:接口不能实例化</a></span><span class="md-toc-item md-toc-h6" data-ref="n102"><a class="md-toc-inner" href="#header-n102">D:接口的实现类</a></span><span class="md-toc-item md-toc-h4" data-ref="n104"><a class="md-toc-inner" href="#header-n104">(3)接口的成员特点：</a></span><span class="md-toc-item md-toc-h6" data-ref="n105"><a class="md-toc-inner" href="#header-n105">A:成员变量</a></span><span class="md-toc-item md-toc-h6" data-ref="n107"><a class="md-toc-inner" href="#header-n107">B:构造方法</a></span><span class="md-toc-item md-toc-h6" data-ref="n109"><a class="md-toc-inner" href="#header-n109">C:成员方法</a></span><span class="md-toc-item md-toc-h4" data-ref="n111"><a class="md-toc-inner" href="#header-n111">(4)类与类,类与接口,接口与接口</a></span><span class="md-toc-item md-toc-h6" data-ref="n112"><a class="md-toc-inner" href="#header-n112">A:类与类</a></span><span class="md-toc-item md-toc-h6" data-ref="n114"><a class="md-toc-inner" href="#header-n114">B:类与接口</a></span><span class="md-toc-item md-toc-h6" data-ref="n116"><a class="md-toc-inner" href="#header-n116">C:接口与接口</a></span><span class="md-toc-item md-toc-h4" data-ref="n118"><a class="md-toc-inner" href="#header-n118">(5)抽象类和接口的区别(自己补齐)?</a></span><span class="md-toc-item md-toc-h6" data-ref="n119"><a class="md-toc-inner" href="#header-n119">A:成员区别</a></span><span class="md-toc-item md-toc-h6" data-ref="n121"><a class="md-toc-inner" href="#header-n121">B:关系区别:</a></span><span class="md-toc-item md-toc-h6" data-ref="n123"><a class="md-toc-inner" href="#header-n123">C:设计理念不同</a></span><span class="md-toc-item md-toc-h4" data-ref="n125"><a class="md-toc-inner" href="#header-n125">(6)练习：</a></span></p></div><h2><a name='header-n2' class='md-header-anchor '></a>1:final关键字(掌握)</h2><h4><a name='header-n3' class='md-header-anchor '></a>(1)是最终的意思，可以修饰类，方法，变量。</h4><h4><a name='header-n4' class='md-header-anchor '></a>(2)特点：</h4><h6><a name='header-n5' class='md-header-anchor '></a>A:它修饰的类，不能被继承。</h6><h6><a name='header-n6' class='md-header-anchor '></a>B:它修饰的方法，不能被重写。</h6><h6><a name='header-n7' class='md-header-anchor '></a>C:它修饰的变量，是一个常量。</h6><h4><a name='header-n8' class='md-header-anchor '></a>(3)面试相关：</h4><h6><a name='header-n9' class='md-header-anchor '></a>A:局部变量</h6><ul><li>a:基本类型 值不能发生改变</li><li>b:引用类型 地址值不能发生改变，但是对象的内容是可以改变的</li></ul><h6><a name='header-n14' class='md-header-anchor '></a>B:初始化时机</h6><ul><li>a:只能初始化一次。</li><li>b:常见的给值
定义的时候。(推荐)
<span>			</span>构造方法中。</li></ul><h2><a name='header-n21' class='md-header-anchor '></a>2:多态(掌握)</h2><h4><a name='header-n22' class='md-header-anchor '></a>(1)同一个对象在不同时刻体现出来的不同状态。</h4><h4><a name='header-n23' class='md-header-anchor '></a>(2)多态的前提：</h4><ul><li>A:有继承或者实现关系。</li><li>B:有方法重写。</li><li>C:有父类或者父接口引用指向子类对象。
<span>	</span></li></ul><p>多态的分类：</p><ul><li>a:具体类多态</li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="java"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="java"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">class</span> <span class="cm-def">Fu</span> {}</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">class</span> <span class="cm-def">Zi</span> <span class="cm-keyword">extends</span> <span class="cm-variable">Fu</span> {}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">Fu</span> <span class="cm-variable">f</span> <span class="cm-operator">=</span> <span class="cm-keyword">new</span> <span class="cm-variable">Zi</span>();</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 72px;"></div><div class="CodeMirror-gutters" style="display: none; height: 72px;"></div></div></div></pre><ul><li>b:抽象类多态</li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="java"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="java"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">abstract</span> <span class="cm-keyword">class</span> <span class="cm-def">Fu</span> {}</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">class</span> <span class="cm-def">Zi</span> <span class="cm-keyword">extends</span> <span class="cm-variable">Fu</span> {}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">Fu</span> <span class="cm-variable">f</span> <span class="cm-operator">=</span> <span class="cm-keyword">new</span> <span class="cm-variable">Zi</span>();</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 72px;"></div><div class="CodeMirror-gutters" style="display: none; height: 72px;"></div></div></div></pre><ul><li>c:接口多态</li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="java"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="java"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">interface</span> <span class="cm-def">Fu</span> {}</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">class</span> <span class="cm-def">Zi</span> <span class="cm-keyword">implements</span> <span class="cm-variable">Fu</span> {}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">Fu</span> <span class="cm-variable">f</span> <span class="cm-operator">=</span> <span class="cm-keyword">new</span> <span class="cm-variable">Zi</span>();</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 72px;"></div><div class="CodeMirror-gutters" style="display: none; height: 72px;"></div></div></div></pre><h4><a name='header-n44' class='md-header-anchor '></a>(3)多态中的成员访问特点</h4><h6><a name='header-n45' class='md-header-anchor '></a>A:成员变量</h6><p>编译看左边，运行看左边</p><h6><a name='header-n47' class='md-header-anchor '></a>B:构造方法</h6><p>子类的构造都会默认访问父类构造</p><h6><a name='header-n49' class='md-header-anchor '></a>C:成员方法</h6><p>编译看左边，运行看右边</p><h6><a name='header-n51' class='md-header-anchor '></a>D:静态方法</h6><p>编译看左边，运行看左边
<span>			</span>
为什么?
因为成员方法有重写。</p><h4><a name='header-n53' class='md-header-anchor '></a>(4)多态的好处：</h4><h6><a name='header-n54' class='md-header-anchor '></a>A:提高代码的维护性(继承体现)</h6><h6><a name='header-n55' class='md-header-anchor '></a>B:提高代码的扩展性(多态体现)</h6><h4><a name='header-n56' class='md-header-anchor '></a>(5)多态的弊端：</h4><p>父不能使用子的特有功能。</p><p>现象：
子可以当作父使用，父不能当作子使用。</p><h4><a name='header-n59' class='md-header-anchor '></a>(6)多态中的转型</h4><p>A:向上转型
    从子到父
B:向下转型
    从父到子</p><h4><a name='header-n61' class='md-header-anchor '></a>(7)孔子装爹的案例帮助大家理解多态</h4><h4><a name='header-n62' class='md-header-anchor '></a>(8)多态的练习</h4><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">A:猫狗案例</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">B:老师和学生案例</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h2><a name='header-n64' class='md-header-anchor '></a>3:抽象类(掌握)</h2><h4><a name='header-n65' class='md-header-anchor '></a>(1)把多个共性的东西提取到一个类中，这是继承的做法。</h4><p>但是呢，这多个共性的东西，在有些时候，方法声明一样，但是方法体。
也就是说，方法声明一样，但是每个具体的对象在具体实现的时候内容不一样。
所以，我们在定义这些<strong>共性</strong>的方法的时候，就不能给出具体的方法体。
而一个没有具体的方法体的方法是<strong>抽象</strong>的方法。
在一个类中如果有抽象方法，该类必须定义为<strong>抽象类</strong>。</p><h4><a name='header-n67' class='md-header-anchor '></a>(2)抽象类的特点</h4><h6><a name='header-n68' class='md-header-anchor '></a>A:抽象类和抽象方法必须用关键字abstract修饰</h6><h6><a name='header-n69' class='md-header-anchor '></a>B:抽象类中不一定有抽象方法,但是有抽象方法的类一定是抽象类</h6><h6><a name='header-n70' class='md-header-anchor '></a>C:抽象类不能实例化</h6><h6><a name='header-n71' class='md-header-anchor '></a>D:抽象类的子类</h6><ul><li>a:是一个抽象类。</li><li>b:是一个具体类。这个类必须重写抽象类中的所有抽象方法。</li></ul><h4><a name='header-n76' class='md-header-anchor '></a>(3)抽象类的成员特点：</h4><h6><a name='header-n78' class='md-header-anchor '></a>A:成员变量</h6><p>有变量，有常量</p><h6><a name='header-n80' class='md-header-anchor '></a>B:构造方法</h6><p>有构造方法</p><h6><a name='header-n82' class='md-header-anchor '></a>C:成员方法</h6><p>有抽象，有非抽象</p><h4><a name='header-n84' class='md-header-anchor '></a>(4)抽象类的练习</h4><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">A:猫狗案例练习</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">B:老师案例练习</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">C:学生案例练习</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">D:员工案例练习</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 96px;"></div><div class="CodeMirror-gutters" style="display: none; height: 96px;"></div></div></div></pre><h4><a name='header-n86' class='md-header-anchor '></a>(5)抽象类的几个小问题</h4><h6><a name='header-n87' class='md-header-anchor '></a>A:抽象类有构造方法，不能实例化，那么构造方法有什么用?</h6><p>用于子类访问父类数据的初始化</p><h6><a name='header-n89' class='md-header-anchor '></a>B:一个类如果没有抽象方法,却定义为了抽象类，有什么用?</h6><p>为了不让创建对象</p><h6><a name='header-n91' class='md-header-anchor '></a>C:abstract不能和哪些关键字共存</h6><p>a:<code>final</code><span>	</span>冲突
b:<code>private</code> 冲突
c:<code>static</code> 无意义</p><h2><a name='header-n93' class='md-header-anchor '></a>4:接口(掌握)</h2><h4><a name='header-n94' class='md-header-anchor '></a>(1)回顾猫狗案例，它们仅仅提供一些基本功能。</h4><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; 比如：猫钻火圈，狗跳高等功能，不是动物本身就具备的，</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; 是在后面的培养中训练出来的，这种额外的功能，java提供了接口表示。</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h4><a name='header-n96' class='md-header-anchor '></a>(2)接口的特点：</h4><h6><a name='header-n97' class='md-header-anchor '></a>A:接口用关键字interface修饰</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">`interface 接口名 {}`</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 24px;"></div><div class="CodeMirror-gutters" style="display: none; height: 24px;"></div></div></div></pre><h6><a name='header-n99' class='md-header-anchor '></a>B:类实现接口用implements修饰</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">`class 类名 implements 接口名 {}`</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 24px;"></div><div class="CodeMirror-gutters" style="display: none; height: 24px;"></div></div></div></pre><h6><a name='header-n101' class='md-header-anchor '></a>C:接口不能实例化</h6><h6><a name='header-n102' class='md-header-anchor '></a>D:接口的实现类</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">a:是一个抽象类。</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">b:是一个具体类，这个类必须重写接口中的所有抽象方法。</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h4><a name='header-n104' class='md-header-anchor '></a>(3)接口的成员特点：</h4><h6><a name='header-n105' class='md-header-anchor '></a>A:成员变量</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">只能是常量</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">默认修饰符：public static final</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h6><a name='header-n107' class='md-header-anchor '></a>B:构造方法</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">没有构造方法</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 24px;"></div><div class="CodeMirror-gutters" style="display: none; height: 24px;"></div></div></div></pre><h6><a name='header-n109' class='md-header-anchor '></a>C:成员方法</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">只能是抽象的</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">默认修饰符：public abstract</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h4><a name='header-n111' class='md-header-anchor '></a>(4)类与类,类与接口,接口与接口</h4><h6><a name='header-n112' class='md-header-anchor '></a>A:类与类</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">继承关系，只能单继承，可以多层继承</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 24px;"></div><div class="CodeMirror-gutters" style="display: none; height: 24px;"></div></div></div></pre><h6><a name='header-n114' class='md-header-anchor '></a>B:类与接口</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">实现关系，可以单实现，也可以多实现。</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">还可以在继承一个类的同时，实现多个接口</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h6><a name='header-n116' class='md-header-anchor '></a>C:接口与接口</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">继承关系，可以单继承，也可以多继承</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 24px;"></div><div class="CodeMirror-gutters" style="display: none; height: 24px;"></div></div></div></pre><h4><a name='header-n118' class='md-header-anchor '></a>(5)抽象类和接口的区别(自己补齐)?</h4><h6><a name='header-n119' class='md-header-anchor '></a>A:成员区别</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">抽象类：</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">接口：</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h6><a name='header-n121' class='md-header-anchor '></a>B:关系区别:</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">类与类：</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">类与接口：</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">接口与接口：</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 72px;"></div><div class="CodeMirror-gutters" style="display: none; height: 72px;"></div></div></div></pre><h6><a name='header-n123' class='md-header-anchor '></a>C:设计理念不同</h6><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">抽象类：is a，抽象类中定义的是共性功能。</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">接口：like a，接口中定义的是扩展功能。</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre><h4><a name='header-n125' class='md-header-anchor '></a>(6)练习：</h4><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">A:猫狗案例，加入跳高功能</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">B:老师和学生案例，加入抽烟功能0</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 48px;"></div><div class="CodeMirror-gutters" style="display: none; height: 48px;"></div></div></div></pre></div>
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